Magic VW engine decoder ring?

OK Chaps (and Chap-ets) I absolutely refuse to start a thread with the title ‘learn me’ as it makes my blood boil, but my current obsession de jour is VW Scirocco’s and I’d like some enlightenment as to VW Engines.

What I’ve gleaned so far is that:

Series 1 Scirocco’s came with a variety of 8V 4cyle engines ranging from 1.5-1.7L in the states (down to 1.1L in Europe). These had either carb or Bosch K Jetronic FI

Series 2 cars came with (I think) 1.7 and 1.8L 8V I the States (as low as 1.3L in Europe) all with K Jetronic, then there was the 1.8L 16V with KE Jetronic.

Now I see people referring to ABA and other alphabet soup engines and saying things like the 1.5 revs better than the 1.6 or 1.7. Heading to the all-powerful Wikipedia doesn’t help me as there seem to be about 42x10^99 different VW group 4 cycle engines. So, can the enlightened souls of GRM give me a VW Engine guide 101 with common upgrades, what’s good, what’s bad and what’s ugly. Please please please don’t just use alphabet soup, but indicate what vehicles and years these letters (engines) come from so I can navigate my way through what’s what?

Thanks folks.

A common upgrade to any 8v Scirocco would be one of the 2.0L options. You can use the 3A code engine, which came in the 88-90 Audi 80 and 90 as pretty much a direct drop in, but they're getting a little scarce. The ABA engine is from the '93-'99.5 Golf and Jetta. It's a 2.0L "tall block", meaning the block is 16.5mm taller for a better rod ratio. You can use that bottom end with the stock head to retain all your current fuel injection so it pretty much becomes a bolt in mod. The AEG code is the '99.5-up 2.0L that's in the Golf, Jetta, and New Beetle, and is pretty much the same as the ABA, except it's got a different oil pump design and the water pump is driven off of the timing belt. The same swap rules apply as the ABA. The 1.8L 16v is a PL code, and they came in the '86-'88 Scirocco, '87-'89 GTI and GLI. The 2.0L 16v is a 9A code, and they can be found in the '90-'92 GTI, GLI, and Passat, and are a direct swap for the 1.8L 16v, and are a HUGE improvement in driveability over the 1.8L 16v. There are about a million different codes for the counter flow 8v engines. Some have solid lifters, some have hydraulic, some have higher compression, some have larger valves, in pretty much any combination. The 1.8t will also bolt up, and there are a bunch of different versions of it as well, and obviously you have to figure out something with fuel management and the like. If you have any more specific questions let me know and I'll see if I can answer them!

Thx Corey, that's just the primer I was looking for. do you happen to know relative weights of 8V Vs 16V or of the 3A Vs ABA?

The 2.0 liter in my old '91 Jetta GLI was a hoot, except when the timing belt changed itself. (That was when my sister owned it.)

And as for what's good, I prefer the 2.0L 16v in the Scirocco chassis. But if you start with an 8v car and don't want a huge project, the ABA with the stock head and an aftermarket cam is an easy swap that will provide some nice power gains and still retain the stock look.

Oh, and can you drop a PL head onto a 3A block (see I'm learning alphabet soup already ) and keep the K jetronic or do you need to do a complete PL 16V swap? Does the PL run on the older K jetronic or do you need to upgrade to the KE?

What are tuning options with the K/KE if you swap cams, exhaust or add compression?

Adrian_Thompson wrote: Thx Corey, that's just the primer I was looking for. do you happen to know relative weights of 8V Vs 16V or of the 3A Vs ABA?

Not right off hand, but all of the 8v engines should be pretty close in weight. I'd say the ABA/AEG is a tiny bit heavier, because of the slightly taller block/longer rods, but not enough to really matter. The 16v is going to be a bit heavier than the 8v, and if I had to guess I'd say 35-50lbs total.

Adrian_Thompson wrote: Oh, and can you drop a PL head onto a 3A block (see I'm learning alphabet soup already ) and keep the K jetronic or do you need to do a complete PL 16V swap? Does the PL run on the older K jetronic or do you need to upgrade to the KE? What are tuning options with the K/KE if you swap cams, exhaust or add compression?

Putting the 16v head on an 8v block will give you goofy compression ratios, because the 8v head has less volume in the compression chamber of the head, so the pistons have more of a dish. If you put the 16v head on a 10:1 compression 8v block, you end up with about 8.5:1 compression. If you put the 16v head on a low compression 8v, I'm not sure if it would even run. Then you also run into problems with the oil pump drive/distributor drive (16v distributor is in the head and the 8v oil pump runs off of the distributor in the block). Oh, and the 3A block is pretty much the same as the 9A block, but with 16v pistons and oil pump drive. So even if you did the proper stuff to put the PL head on a 3A block, you'd pretty much end up with a 9A engine. If you want to do a 16v swap, it's best to just get a complete 16v engine and KE or K-motronic swap. There are wiring diagrams readily available online and they're super easy to wire up/change over.

With K-jetronic (or CIS, whatever you want to call it) you can adjust the fuel ratio with the 3mm screw at the fuel distributor, but the idle gets weird if you go too far with it. KE (or CIS-E) can be adjusted there too, but the computer generally doesn't like it very much. Autotech made a pretty nice adjustable fuel enrichment module that works pretty well. And K Motronic (or CIS-M) is chippable, and TT makes a pretty nice chip for the 2.0L16v.

Adrian_Thompson wrote: other alphabet soup engines and saying things like the 1.5 revs better than the 1.6 or 1.7.

This is something I don't understand. As a car guy we hear this all the time. "Oh those low displacement motors rev better than the larger ones" You hear it from Alfa guys bemoaning how those 2 liters don't rev like the 1.5 did. We have been hearing this forever and it doesn't make sense.

The ability of the needle to climb up the tach in gear is proportional to the power being produced. A larger more powerful motor will do so faster than its less powerful smaller counterpart. Or by "revs better" do they mean unloaded? If so what is the point? Last time I checked goosing the throttle from idle to redline in neutral never won a race. Better for rev matching would be my only guess.

A smaller less powerful motor cannot rev better (whatever that even means) while it is moving the car. In the case of the VW 1.5, 1.6 and 1.7 lumps with their absurdly overbuilt, heavy ass pistons and tiny port heads, they can barely rev at all. Just swap in a 16V or ABA.

/rant off

Next silly Q.

Gearboxes, I understand the 020 (I think) gearbox has an open diff, but that it can be shimmed to act like an LSD without dropping $800-1,000 on a real LSD. What’s the low down? IS this fact or fiction? how well does it work? how long does it last? Does the car sprout baby unicorns as well?

A couple places used to sell shim kits, but I really don't know how much it helps. I had one in my '87 GTI, and it seemed to help, but it also seemed to accelerate the self-machining syndrome. If you're not familiar with SMS, that's when the rivets that connect the ring gear to the differential come loose, and the ring gear eats a hole in the case. In my (quite built) '87 GTI 16v, I went through 3 transmissions (all from the junkyard) in a year after I installed the shim kit. When I installed the fourth one I was in a hurry, so I didn't swap in the shim kit. That transmission is still in the car 15 years later.

There were some real LSDs on ebay (OBX maybe?) for around $400, otherwise $1000 for a Quaife or Peloquin are the only real choices. I personally don't trust the shim kit or a phantom grip to do much. Oh, and make sure you've got a close ratio gearbox. The wide ratio boxes aren't nearly as much fun.

The peloquin 80% kit is what you are thinking of. It only works with some of the 84 and up transmissions with the spring loaded diffs.

http://www.peloquins.com/products_80.html

They do work quite well but wear fast. That tapered bronze shim is what wears and you can keep swapping them out when your car starts doing the one tire fire again.

I ran those for years. They start to wear at about 6 months in a daily driver and by 9 months you don't notice them anymore. Pop in the new shim and the magic starts to happen again.

Those kits are beautiful. I ran one and as ditch digger said you do have to keep on top of updating but it really helps. Also there is a kit to replace the rivets with bolts that helps the SMS.

You aren't to far from me, I have a spare 2.0 16v sitting here with an extra 'Rocco 5spd PM me if interested....

I used an OPM Motorsports LSD in my aba/CIS counterflow headed 81 Scirocco. Worked great with no problems.

Two different 1.8 8 valve engines.. Different head bolt patttern.

chandlerGTi wrote: You aren't to far from me, I have a spare 2.0 16v sitting here with an extra 'Rocco 5spd PM me if interested....

Tempting, but I don't have a car or money for one yet, this is in the evil planning stage right now............

iceracer wrote: Two different 1.8 8 valve engines.. Different head bolt patttern.

Que?

This is a new one on me. Which engine is different? I thought the head bolt pattern never changed from the original 1.5's in 1975 all the way through the ABA's of the late 90's, including diesels and 16v's.

I know the oil ports on the heads changed in 84 for the JH "big valve" head and it was common to have them modded so you could run that head on your 1.6 or 1.7 blocks. My dad and I did it in the late 80's.

ditchdigger wrote:

Adrian_Thompson wrote: other alphabet soup engines and saying things like the 1.5 revs better than the 1.6 or 1.7.

This is something I don't understand. As a car guy we hear this all the time. "Oh those low displacement motors rev better than the larger ones" You hear it from Alfa guys bemoaning how those 2 liters don't rev like the 1.5 did. We have been hearing this forever and it doesn't make sense. The ability of the needle to climb up the tach in gear is proportional to the power being produced. A larger more powerful motor will do so faster than its less powerful smaller counterpart. Or by "revs better" do they mean unloaded? If so what is the point? Last time I checked goosing the throttle from idle to redline in neutral never won a race. Better for rev matching would be my only guess. A smaller less powerful motor cannot rev better (whatever that even means) while it is moving the car. In the case of the VW 1.5, 1.6 and 1.7 lumps with their absurdly overbuilt, heavy ass pistons and tiny port heads, they can barely rev at all. Just swap in a 16V or ABA. /rant off

Usually, lower displacement engines have less reciprocating mass and a shorter stroke which makes for easier revs (the VW engines you cited notwithstanding). The difference was readily apparent with the FIAT twincam motors from the '60s-'70s. The 1.4 -1.6 liter variants were much peakier than the 2.0. Of course, the valves and port sizes did not change significantly with the increase in volume so that plays a part as well. The 1.6 really woke up above 4,000 rpm but the 2.0 had much better torque 1,000 to 1,500 rpm lower. Either is fine, depending on the engine's intended use.

The smaller VW engines you mentioned obviously had a lot of reciprocating mass. Big block Chevy motors revved faster than big-block Buicks of similar displacement because Buicks came with massive full-skirted pistons that looked like something out of a Caterpillar bulldozer.

ditchdigger wrote:

iceracer wrote: Two different 1.8 8 valve engines.. Different head bolt patttern.

Que? This is a new one on me. Which engine is different? I thought the head bolt pattern never changed from the original 1.5's in 1975 all the way through the ABA's of the late 90's, including diesels and 16v's. I know the oil ports on the heads changed in 84 for the JH "big valve" head and it was common to have them modded so you could run that head on your 1.6 or 1.7 blocks. My dad and I did it in the late 80's.

And actually all the way up to the '08 or so 2.0L fsi turbo. There are a few minor differences, but nothing that can't be overcome.

use the kr engine more komp add a set off 45 mm and 2,5 exust then you have a sound and power that will make your head spin ass wel the wheels

I just learned more about VW engines in this thread than I did in 4 years on VW Vortex. I had a JH head on a GX block which is as far as I got with the alphabet soup. You can swap in an ABA head and eliminate CIS or add ITBs. My recollection is that just about any trans will mate up to just about any engine. These cars are like Legos; I want another one.